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4 v mEq 93m mim UB NQ FSQ R T3 um ma NThQ NN S TMQ @nml TQ .N O U s m EE. NP M I, LC Wm E E U. MY m V w @di ATTORNEY United States Patent O i3,125,642. HIGH-SPEED STEERING CIRCUIT FOR FRE- QUEN CY SHIFT PULSESENDER Lynn T. Anderson, Gahanna, and Charles E. Kress Columbus, Ohio,assignors to Bell Telephone Laboratories, IYncol-porated, New York, N. acorporation of New Filed Jan. 1S, 1962, Ser. No. 166,328 11 Claims. (Cl.179-18) This invention relates to a frequency shift pulse sender, andmore particularly to a high-speed steering circuit for-frequency shiftpulse senders.

Frequency shift pulse senders are used in data or voice communicationsystems where transmission of information from one point to another ison a frequency shift pulse signaling basis, information beingtransmitted by frequency shift pulses applied over the tip and ringconductors of the line. Commonly, a single voice frequency is utilizedwhich is shifted to produce marking signals, each digit or bit ofinformation being represented by a different combination of mark(direct-current output) and/ or space (no direct-current output)signals, each combination occupying six time spaces. In addition to thecombinations assigned to the digits or other information bits, a -of-6combination (KP) is assigned as a gate opener pulse and a different2-of-6 combination is assigned as an end-of-pulse signal. These last twocombinations serve, respectively, to activate and deactivate thefrequency shift receiver or detector.

As one illustrative example, frequency shift pulse senders may be usedin present crossbar telephone switching systems, within the switchingcenter, in conjunction with the other basic circuits in a manner similarto that in which multifrequency senders are commonly used. The use of amultifrequency sender in an automatic telephone switching system isdisclosed, for example, in I. W. Gooderham et al. Patent 2,868,884,January 13, 1959, while A, I. Busch Patent 2,585,904, February 19, 1952,discloses an automatic telephone system of the crossbar type inconjunction with which multifrequency senders and frequency shift pulsesenders can advantageously be utilized.

In accordance with the normal operation of a crossbar telephone system,the originating subscriber dials into an originating register thecalling information, that is, the area code, where required, the officecode and the numerical digits. When the entire number information hasbeen received it is transferred to the marker by the originatingregister. The marker then selects an idle sender, connects theretothrough the outgoing sender connector, and at the same time selects anidle trunk and connects the sender thereto by means of the sender link.

Through the outgoing sender connector, the marker now transfers to thesender all the information necessary for completion of the call; thisincludes the control digit, the number of digits to delete, if any, thearbitrary digits to be prefixed, if any, and the type of trunk.(Arbitrary added digits are usually utilized in code conversion or codepreixing, while some or all of the code digits may be deleted whendirect trunks are available to the called office.) When the senderreceives the advance signal from the marker, it proceeds to outpulse theKP, start-pulsing or begin-pulsing signal, the required digits, and theendof-pulsing signal. Following this the sender is released.

In present day communication systems, especially in the instance of datasystems, the requirement of high speed transmission is paramount andtransmission at rates of the order of 75 digits per second iscontemplated. Provision of a sender circuit capable ofL operating at arelatively high speed therefore becomes important.

Accordingly it is an object of our invention to substan- 3,125,642Patented Mar. v17, 1964 lCC tially enhance the performance ofa frequencyshift pulse sender with regard to its operating speed.

Another object of the invention is to improve the operation of the digitsteering circuit of a frequency shift pulse sender.

In accordance with a specific embodiment vof the irl-- vention afrequency shift pulse sender is provided with a scanning circuit dividedinto two areas, a first order or odd area and a second order or evenarea. The digit steering circuit comprises two paths, or rails, oneconnected to the odd area of the .scanninglcircuit and the otherconnected to the even area thereof. First order or odd and second orderor even digits are transmitted alternately over the respective paths tothe respective scanning areas. During an even scan the steering circuitguides the next odd digit to the odd digit scan area, during the oddscan the next even digit is prepared, and so on. Means are included forcompensating for the addition of arbitrary digits and the deletionofregistered digits, which actions are inherent in the operation of thesender, whereby to assure that each digit is steered to the proper areaof the scanning circuit.

A feature of our invention is a scanning circuit having an odd area andan even area.

A further feature of the invention is a two-path digit steering circuit,one path connected to the odd area of the scanning circuit and the otherpath connected to the even area thereof.

A still further feature of the invention is means effective when eitherclass (odd or even) digit is being scanned for preparing the next digitof opposite class for scanning.

Yet another feature of the invention is the provision of reversingrelays effective upon operation to reverse the feeding paths from onescanning area to another whereby to compensate for the addition ofarbitrary digits and/ or the deletion of registered digits.

A full understanding of the arrangement contemplated by the invention,as well as an appreciation of the various features thereof, may begained from consideration of the following detailed description inconnection with the accompanying drawing, in which:

FIG. 1v shows schematically one way in which .thefrequency shift pulseoutgoing sender contemplated bythe present invention may be associatedwith other portions of an automatic telephone system;

FIGS. 2 and 3 show the digit registration circuit of one specificillustrative embodiment of the frequency shift pulse outgoing sendercontemplated by the invention;

FIGS. 4 and 5 show the scanner feeding path of the sender;

FIG. 6 shows the digit steering circuit;

FIG. 7 shows lschematically the arrangement and relationship of thescanner, scanner feed paths .and other elements of the sender inaccordance with our invention and the immediately cooperating portionsof the system; and

FIG. 8 is a key diagram showing howFIGS. 2 through 6 should be joinedtogether.

General Description of Telephone System Including Frequency Shift PulseSender A general and a detailed description of the novel circuitsincluded in thefrequency shiftpulse sender contemplated by the inventionwill be given subsequently with particular reference to F'IG. 7 andFIGS. 2 to 6, respectively. However, there will irstkbe given a briefgeneral description of a type of system in connection with .which thefrequency shift pulse lsender may be used. Referring to FIG. 1,therefore, calling line 11 is connected .to originating register 12 by adial-'tone connection, as indicated, through the line link frame 13 andthe trunk lin-k frame 14. The subscriber after hearing dial-tone dialsthe iarea code, where required, the office code and the numerical digitsinto register 12. (The elements represented in FIG. 1 as associated Withthe contemplated frequency shift pulse sender 17 are well known in theart with regard both to arrangement and operation `and will not bedescribed in detail.)

When the entire number has been received, originating register 12transfers it to marker 18 which translates the lcode and determines thatthe called oilice requires frequency shift pulses. Marker 18 thenselects an idle frequency shift pulse sender (here assumed to befrequency shift pulse outgoing sender 17) with access to an outgoingtrunk, and connects thereto by means of outgoing sender connector 21.Marker 18 also selects an idle outgoing trunk 22 and connects trunk 22to sender 17 by means of outgoing sender link 23.

Outgoing sender connector 21 commonly consists of two channels, one acontrol channel which is individual to the sender and marker, and theother -a common channel which is common to a group of senders andmarkers and which carries a majority of the connecting leads. Throughthe outgoing sender connector 21, the marker now transfers rto frequencyshift pulse sender 17 all the infomation necessary for the completion ofthe call. This information includes the dialed number, the number ofdigits to delete, the arbitrary digits to be prefixed, and the type ofoutgoing trunk. The marker also at this time causes a connection to beestablished between the calling line 11 and the outgoing trunk -22through line link frame 13 and trunk link frame 24.

When marker 18 has checked the connection between the calling line andthe `outgoing trunk, the connection between the outgoing trunk and thesender, and has checked that sender 17 has received the correctinformation through outgoing sender connector 21, it transmits anadvance (AV) signal to the sender through the control channel referredto above as an indication that sender 17 should assume supervision andcomplete the call.

As will be described in detail subsequently and shown generally in FIG.7, frequency shift pulse sender 17 includes among its circuits, a digitregistration circuit 34, a digit steering circuit 35, a scanning circuit25 and a scanner feeding circuit including paths 30, 31 and associatedcontact networks 32, 33 and reversing relay contacts 39. The novelcircuit arrangement contemplates first order and second order areas inthe scanning circuit, which will be referred to, respectively, as theeven area and the odd area, with means for transmitting odd and evendigits alternately to the respective areas. During an even scan thesteering circuit guides the next odd digit to the odd digit scan, duringthe odd scan the next even digit is prepared, and so on. Reversing relaycontacts 39 are included in the feeding paths 30, 31 which contacts uponoperation reverse the feeding paths 30, 31 from one scanning area toanother whereby to compensate for arbitrary digit addition or thedeletion of digits and assure that each digit is steered to the properrespective scanning area.

After sender 17 has pulsed out all the digits registered, it transferssupervision to outgoing trunk 22 and releases. The call then progressesto-ward completion in the normal manner.

Since it is inherent in the sender operation that the system may operatein la number of ways, namely that no arbitrary digits may be added orthat one, two or three arbitrary digits may be added, and that noregistered digits may be deleted or that from one to six registereddigits may be deleted, it will be readily apparent that a substantialnumber of combinations are possible. As just one example, a digit whichis normally odd, that is when there are no :additions or deletions, maybecome even when there are an odd number of deletions, may again be oddwhen there are an even number of digits deleted and an even number ofdigits added, and so on. In order that the continuous scanning rate,which is attained by the provision of the odd-even areas and which isimportant in the proper functioning of the sender, may be maintained, itis necessary, of course, that the digits continue to be supplied on analternate odd-even basis in spite of the additions or deletionsintroduced. Also it is necessary that the order of the registers bemaintained, that it be added to, or that it be subtracted from accordingto the changes introduced, if any, by addition or deletion. Stillfurther, changes in the locking paths of the steering relays must bemade on occasion whereby the chain operation be maintained in accordancewith which the operation of each relay of one order is followed -byrelease of the previouslyoperated relay of that same order. All of thesevarying situations lare successfully met by the novel arrangementcontemplated by the invention.

General Overall Description of Principal Portions of System Included inand Immediately Associated With Sender yIt is believed thatunderstanding of the subsequent detailed description of the frequencyshift pulse sender 17 will be facilitated by rst considering at thispoint a brief general description, with reference to FIG. 7, of certainportions of the system which are immediately associated with, oractually included in, the sender. Referring to FIG. 7, therefore, thescanning circuit 25 is indicated with its respective even and odd areas,the two respective feed paths or lines also being shown as paths 30 and31. Actually paths 30 and 31, which will also be referred to herein aslines, each comprise six digit leads, 0, 1, 2, 4, 7 and 10, as describedsubsequently and as shown in FIGS. 4 and 5 of the drawing. Theinformation supplied to the respective areas of the scanning circuit isin the nature of particular combinations of grounds or opens connectedconsecutively to the respective feed paths; these connections aredetermined in turn by the momentary condition (closed or released) ofregister relay contacts as represented in the drawing by capitionedboxes 32 and 33. The condition of the register relay contacts is, ofcourse, determined -by the condition of the register relays themselves(captioned box 34); as will be described subsequently the registerrelays are conditionsd, i.e., operated or released, in accordance withthe calling digit information ystored in the digit registration circuitfrom the marker 18.

The paths 30 and 31 are activated in turn, under control of Ithe digitsteering circuit 35 (shown in detail in FIG. 6), to supply digitinformation, as determined by the register relays, to the respectiveeven and odd areas of scanning circuit 2S; the output from the scanneris applied over an output path 36 to control frequency shift pulser 38,the output of which, in turn, is supplied to outgoing sender link 23.

As indicated above, and as will be described in detail subsequently, itbecomes necessary in the event of certain deletions of digits and/ orcertain additions of arbitrary digits to, in effect, temporarily reversethe connections of paths 3l) and 31 toy the respective areas of scanningcircuit 25; in accordance with the novel arrangement contemplated by thepresent invention this reversal is accomplished through reversing relaycontacts represented by captioned box 39. The reversing relays,similarly to the register relays and also represented by captioned box34, are operated in accordance with information supplied by marker 18,specifically in accordance with delete and/ or add instructions includedin the calling information.

Detailed Description of Frequency Shift Pulse Senderl Referring now tothe additional figures of the draw-4 ing, the digit registration circuitof frequency shift pulse outgoing sender 17 is shown in FIGS. 2 and 3;the digit registration circuit of FIGS. 2 and 3 together with thereversing relay circuit of FIG. 4 comprise the register and reversingrelays 34 of FIG. 7. As pointed out above the information recorded inoriginating register 12 iS transferred by the marker to the senderthrough outgoing sender connector 21; this information is recorded inthe digit registration circuit in the same order as it was recorded inthe originating register. The code and numerical digits are registeredin the digit registration circuit on a two-out-of-ve basis.

One of the digit register units, AR, is shown in detail in FIG. 2 andthe other thirteen units, BR, CR, A, B, C, D, E, F, G, H, J, K and L areindicated by captioned boxes since all are alike in detail. Each unitcomprises a suitable housing enclosing ve dry-reed register relays; inthe instance of the AR unit, for example, these relays are designatedARG, AR1, AR2, AR4, and AR7. Two of these relays Will operate when an ARdigit is registered. In addition to the registered information an extrasignal is generated locally for KP and start purposes, and appears onthe lead of the feed paths 3@ and 31, as described further below.

Provision is made in the sender for registering up to three arbitrarydigits; as pointed out above these arbitrary digits originate in themarker and are commonly utilized for code conversion and code prexing..Any digits registered on the arbitrary digit registers AR, BR, CR, willbe transmitted ahead of digits registered on the A to L units. A singlearbitrary digit will be registered on unit CR, two arbitrary digits willbe registered on units CR and BR and three arbitrary digits will beregistered on the AR, BR and CR units. In connection with theseregistrations, relay DCR is operated if one digit is added, relays DBRand DCR are operated if two digits are added and relays DAR, DBA and DCRare operated if three digits are added. As indicated by the dot-dashlines and brackets, operation of these relays is under control 0f pathsof the registration circuit not shown in detail since the details ofthose paths are not directly involved in the present instance.

As also pointed out above, in many instances, particularly when directtrunks are available to the called office, the sender will be requiredto omit or dele-te some or all of the code digits. This is accomplishedunder control of delete signals from the marker through the outgoingsender connector 21 which, as indicated by the dot-dash lines andbracket, are applied to delete relays DL1 to DL6.

Relay AEV (add even), FIG. 4, will operate if an even number (0 or 2) ofarbitrary digits are added and relay DLOD, FIG. 4 (delete odd), willoperate if an odd number of digits are deleted; these two relayscomprise the reversing relays of box 34 of FIG. 7. That is, if zeroarbitrary digits are added, relay AEV operates through make contactON1-1 and break contacts DAR-1 of relay DAR and DCR-1 of relay DCR whileif two digits are added the operate path is through make contact ON1-1of relay ON1, break contact DAR-1 of relay DAR, and make contact DBR-1of relay DBR. If one (odd) arbitrary digit is added relay AEV remains inreleased, or nonoperated, position since the operate path is open atbreak contact DCR-1 of relay DCR. The respective operate paths for relayDLOD are completed through either make contact DLI-1 of relay DLI, DLS-1of relay DL3 or DLS-1 of relay DLS. It will be apparent from FIG. 4 thatcontacts of relay AEV when operated reverse the feeding paths 30, 31 tothe electronic scanning circuit for all digits after AR; the lockingpath for relay KP (FIG. 6) is also reversed as subsequently described.It will also be apparent from FIGS. 4 and 5 that contacts of relay DLODupon operating reverse the feeding paths 31, 3i) for all steering relaysafter CRS; the locking paths for the KP relay and arbitrary digitsteering relays are also reversed. In the schematic showing of FIG. 7discussed above the reversing actions just referred to are performed bythe reversing relay contacts, box 39.

N0 Arbitrary Digits Added; No Registered Digits Deleted It will beassumed now that the entire calling information has been recorded in thedigit registration circuit, that no arbitrary digits have been added, nodigits have been deleted, and that the off-normal relays ON and ON1 andthe advance relay ,AV have been operated by the advance signal from themarker over the respective operate paths (not shown in detail). RelayAEV (FIG. 4) will be operated and relay DLOD (FIG. 4) will be inreleased position. Relay KP (FIG. 6) operates from ground, make contacts`ON-l of relay ON and AV-l of relay AV, break contacts SP-1 of relay SPand KP-l of relay KP, winding of relay KP to battery. (Relay SP, whichit is noted is in released condition at this point, operatessubsequently in connection with a trunk test function of the overallsystem, a function which is not immediately concerned with the sendercircuit contemplated by the invention.) Relay KP upon operating locks toground through its make contact KP-2, make contact AEV-1 of relay AEV,lead 27, break contacts CRS-1 of relay CRS, DLOD-1 of relay DLOD, BS-1of relay BS, DS-1 of relay DS, FS-l of relay FS, HS-l of relay HS, KS-lof relay KS, STS-1 on relays STS, lead 28, make contact ON-l of relay ONto ground. Also at this time, since no arbitrary digits were added andno registered digits deleted, relay AS (A digit steering), FIG. 6,operates over a path from ground, makecontacts ON-l of relay ON and AV-lof relay AV, break contacts SP-2 of relay SP, DAR-2 of relay DAR, DBR- 2of relay DBR, DCR-2 ofrelay DCR, DLI-2 of relay DLI, DLS-2 of relay DLS,DLS-3 of relay DLS, DLG-1 of relay DL6, DL4-1 of relay DL4, and DL2-1 ofrelay DLZ, break contact AS-1 and winding ofrelay AS to battery; relayAS upon operating locks to ground through its make contact AS-IS, breakcontacts CS-3 of relay CS, ES-1 of relay ES, GS-l of relay GS, LIS-1 ofrelay IS, LS-l of relay LS, STSl-l of relay STS1, lead 28, make contactON-l of relay ON to ground. Thus two relays (in this instance KP and AS)in the steering chains are operated before the steering and scanningactually begins.

Scanning circuit 25 is preferably of the electronic type with continuousseries scanning `of the even-odd areas; the circuit is not shown indetail since the exact arrangement is not essential in the presentinstance. A frequency shift pulser 3S is controlled by the scanningcircuit output whereby to supply the mark-space signals to the linecorresponding to the output-no output or on-otf information supplied tothe scanning circuit over the scanner feeding path. Relays PGE and PGO(FIG. 4) are also controlled by scanning circuit 25, relay PGE operatingfrom an even scan and relay PGO operating from an odd scan.

Grounds permanently wired for the 5-of-6 start pulsing signal areimmediately connected to the 0, 1, 2, 4 and l0 leads of path or line 30and thus to the even area of the scanning circuit (FIG. 4) through makecontacts KP- 12, KP-llt, K13-16, KP-IS, and KP-22 of relay KP, the pathtoward the other steering relay contacts being opened at break contactsICP-1I, IiP-13, KP-IS, KP-17, KP- 19 and KP-Zl. At the same time theclosed contacts of the A register relays A0, A1, A2, A4, and A7 (whichcontacts are contemplated as included in contact networks 32 of FIG. 7),for the rst digit are connected through make contacts of the operated ASrelay AS-Z, .AS-4, AS-6, AS-S, and AS-10, break contacts of the BRSrelay, BRS-2, BRS-4, BRS-6, BRS-8, BRS-10 and BRS-11, make contacts ofthe AEV relay, AEV-3, AEV- 4, AEV-6, AEV-8, AEV-10, and AEV-12, andbreak contacts of the ARS relay, ARS-A1, ARS-3, ARS-*5, ARS- 7, ARS-9and ARS-11. Thus the information to be supplied to the scanning circuitwith regard to the A digit, that is the particular combination of groundand opens, will be determined by the condition, operated or nonoperated,of the respective A register relays. (In the '7 above and subsequentinstances, contact designations common to a particular relay areindicated on the drawing by a single bracket.)

The rst steering pulse is generated by the scanning circuit 25 (FIG. 4)during scanning of the KP pulse and triggering of shift pulser 38, andcontinued during the scanning interval of the digit which is long enoughto operate the proper relay in the steering circuit. Since this is evenpulse, relay PGE (FIG. 4) operates and the pulse is repeated over a pathfrom ground, make cntacts ON-l of relay ON (FIG. 6), AV-l of relay AV,PGEJ of relay PGE and IiP-23 of relay KP, break contacts DAR-3 of relayDAR, DBR-3 of relay DBR, DCR- 3 of relay DCR, DLI-3 of relay DLI, DLS-3of relay DLS, DLS-4 of relay DLS, DL62 of relay DL6, DL4-2 of relay DA,BLZ-2 of relay DL2, and BS-S of relay BS, winding of relay BS tobattery; relay BS operates over this path and locks to ground through apath including its make contact BS9, break contacts DS-l of relay DS,FS-l of relay FS, HS1 of relay HS, KS-lt of relay KS and STS-1 of relaySTS, lead 28, and make Contact ON-l of relay ON to ground.

When relay BS (FIG. 6) operates, the previouslytraced locking path ofrelay KP is interrupted at break contact BS-l of relay BS but isimmediately transferred to make contact BS-24 of the same relay andcompleted j over a path through break contacts DLE-2 of relay DLZ, DL4-2of relay DIA, DL6-2 of relay DL6, DLS-4 of relay DLS, DLS-3 of relayDLS, DLI-3 of relay DLI, DCR-3 of relay DCR, DBR-3 of relay DBR, andDAR-3 of relay DAR, make contacts KP-23 of relay KP, PGE-1l of relayPGE, AV-l of relay AV, and ON-l of relay ON to ground.

Relay PGE releases at the end of the KP digit scanning cycle; release ofthe PGE relay is followed by release of the KP relay since theabove-traced holding path is opened at make contact PGE-l of relay PGE.The lines included in the previously-discussed path Btl are thereforeclosed to the even area of scanning circuit 25 (FIG. 4) through breakcontacts KP-Ill, IiP-13, KID-15, IiP-17, KP-19 and KP-Zl of relay KP.

In the instance of the KP relay just discussed and of other steeringrelays discussed subsequently, it will be noted that, While a firstlocking path for the respective relay is interrupted by other relayoperations, a second locking path is established immediately to hold theparticular steering relay operated until the particular scan period hasbeen completed and the respective PGE (even pulsing) or PGO (oddpulsing) relay has released. This operation assures proper pulse length.

As pointed out above the rst odd pulse (register A) was connected to theodd scanning area through make contacts of the AS relay. (With referenceto FIG. 7, previously discussed, register relay contacts involved in theconnection would be included in contact networks `of that figure.) Aspreviously pointed out, register A vARil, ARI, AR2, AR4, and AR7 (FIG.2) of the AR register. The A digit, the rst odd digit, is now scannedtherefore and the second steering pulse is generated. Since this is anodd pulse, relay PGO (FIG. 4) operates and the pulse is repeated over apath from ground, make contacts ON-l of relay ON (FIG. 6), AV-l of relayAV, PGO-1 of relay PGO, and AEV-26 of relay AEV, break contacts BRS-13of relay BRS, DLOD-Z of relay DLOD, make contact AS14 of relay AS, breakcontact CS-l of relay CS, and winding of relay CS to battery; relay CSoperates and locks through its make Contact CS-Z, break contacts ES-l ofrelay ES, GS-l of relay GS, .IS-1 of relay IS, LS-l of relay LS, STSl-lof relay STSl, lead 28, and make contact ONA of relay ON to ground.

When relay CS (FIG. 6) operates, the holding path previously traced forrelay AS is interrupted at break Contact CS-S of relay CS but isimmediately transferred to make contact (3S-1S of relay CS and completedt0 ground through make contact AS-lf of relay AS, break contacts DLOD-26of relay DLOD and BRS-13 of relay BRS, make contacts AEV-26 of relayAEV, PGO-l of relay PGO, AV-ll of relay AV, and ON-l of relay ON toground.

Relay PGO releases at the end of the A digit scanning cycle and this isfollowed by release of relay AS since the abovetraced locking path isinterrupted at make contact PGO-ll of relay PGO.

The next even pulse (register B) having been connected to the evenscanning area through operation of relay BS of the steering circuit(FIG. 6), which action corresponds to control of path 3i) by the digitsteering circuit 35, FIG. 7, operated contacts of the B register relayBtl, Bl, B2, B4, and B7 are connected through make contacts BS-Zlil,BS-lz, BS-14, BS-Il, and BS-18 of relay BS, break contacts DLOD-3,DLOD-S, DLOD7, BLOB-9, DLOD-ll and BLOB-13 of relay DLOD, break contactsCRS-7, CRS-4, CRS-2, CRS-9, CRS-11 and CRS-I3 of relay CRS, makecontacts AEV-14, AEV-17, AEV-1S, AEV-2l, AEV-Z3 and AEV-24 of relay AEV,and break contacts KP1L IiP-13, KP-15, IiP-17, KP- llt and IiP-2l ofrelay KP to the even area of the scanning circuit, and this even pulseis scanned. At this same time the next odd digit (C register) isconnected to the odd scanning area through make contacts (2S-4, CS-e,(2S-8, CS-ltl, and CS-lilz of relay CS, break contacts DLOD-14, DLOD-16,DLOD-18, DLOD-2@, DLOD-ZZ and DLOD-24 of relay DLOD, break contactsAS-3, AS-S, AS-7, AS-9, AS-ll, and AS-IS of relay AS, break contactsBRS-2, BRS-4, BRS-6, .BRS-8, BRS-itl and BRS-1l of relay BRS, makecontacts AEV-3, AEV-4, AEV-6, AEV-S, AEV- ltll, and AEV-12 of relay AEV,and break contacts ARS-l, ARS-3, ARS-5, ARS-7, ARS-9 and ARS-11 of relayARS to the odd scanning area. This follows from operation of relay CS(FIG. 6) of the digit steeering circuit as described above andcorresponds to activation of path 31 (FIG. 7) under control of digitsteering circuit 35.

The next steering pulse is generated during scanning of the B digit andrelay PGE (FIG. 4) operates. The even pulse is then repeated fromground, make contacts ON-l of relay ON (FIG. 6), AV-l of relay AV, PGE-1of relay PGE, break Contact IiP-24 of relay KP, make contact AEV-Z7 ofrelay AEV, break contacts ARS-13 of relay ARS, CRS-14 of relay CRS,DLOD-27 of relay DLOD, make contact ISS-22 of relay BS, break contactDS-Z and winding of relay DS to battery; relay DS operates over thispath and locks to ground through its make Contact DS-S and breakcontacts FS-l of relay FS, HS-l of relay HS, KS-l of relay KS, STS-1 ofrelay STS and over lead 2S to ground,

When relay DS (FIG. 6) operates, the previously-traced holding path ofrelay BS is interrupted at break contact DS-l of relay DS. However, theholding path is irnmediately transferred to make contact DS-llS of relayDS and completed to ground through make contact BS-22 of relay BS, breakcontacts DLOD-27 of relay DLOD, CRS-14 of relay CRS, and ARS-13 of relayARS, make Contact AEV-27 of relay AEV, break contact KP-24 of relay KP,make contacts PGE-1 of relay PGE, AV-1 of relay AV and ON-l of relay ONto ground.

Relay PGE (FIG. 4) releases at the end of the B digit scanning cycle andthis is followed by release of relay BS since the above-traced holdingpath is interrupted at make contact PGE-1 of relay PGE.

Closed contacts of the D register relay group, D0-2, Dlt-2, DZ-Z, Dfi-2,and D7-2 (FIG. 5) representing the next even digit (and presumed to beincluded in contact networks 32 of FIG. 7) are now connected to the evenarea of the scanning circuit through make contacts DS-4, DS-6, DS-S,DS-ll, and DS-12 of relay DS, break contacts BS-ll, BS-13, BS-15, BS-17,BS-19, and BS-21 of relay BS, break contacts DLOD-3, DLOD-5, DLOD-7,DLOD-9, DLOD-11 and DLOD-13 of relay DLOD, break contacts CRS-7, CRS-4,CRS-2, CRS-9, CRS-11 and CRS-13 of relay CRS, make contacts AEV-14,AEV-47, AEV-18, AEV-21, AEV-A23 and AEV-24 of relay AEV, and breakcontacts KP-11, KP-13, KP-15, KP-17, KP#19 and KP-Z1 of relay KP to theeven area of the scanning circuit.

The odd pulse resulting from scanning the C register digit is repeatedfrom ground, make contacts ON-l of relay ON (FIG. 6), AV-l of relay AV,PGO-1 of relay PGO, make contact AEV-26 of relay AEV, break contactsBRS-13 of relay BRS, DLOD-26 of relay DLOD, AS-16 of relay AS, makecontact CS-16 of relay CS, break contact ES-Z and Winding of relay ES tobattery; relay ES operates over this path and locks to ground throughits ES-3 make Contact, break contacts GS-l of relay GS, I S-1 of relayJS, LS-1 of relay LS, STSl-l of relay STSl, lead 28 to ground.

When relay ES (FIG. 6) operates, the previouslytraced holding path forrelay CS is interrupted at break contact ES-1 of relay ES, but isimmediately transferred to make contact S-18 and completed to groundthrough make contacts CS16 of relay CS, break contact AS-16 of relay AS,break contacts DLOD-26 of relay DLOD and BRS-13 of relay BRS, makecontacts AEV-26 of relay AEV, PGO-1 of relay PGO, AV- of relay AV andONwl of relay ON.

Relay PGO releases at the end of the odd C digit scanning cycle; this isfollowed by release of relay CS since the above-traced holding path isinterrupted at make contact PGO-1 of relay PGO.

Closed contacts of the E register relays E0, E1, E2, E4, and E7 (FIG.5), representing the neXt odd digit and corresponding to contacts ofcontact network 33 (FIG. 7) are now connected to the odd scanning areathrough make contacts ES-4, IES-6, ES-S, ES-10, and ES-12 of relay ES,break contacts CS-S, CS-7, CS-9, CS-11, CS-13 and CS-IS of relay CS,break contacts DLOD-14, DLOD-16, DLOD-18, DLOD-20, DLOD-22 and DLOD-24of relay DLOD, break contacts AS-3, AS-S, AS-7, AS-9, AS-11 and AS-13 ofrelay AS, break contact BRS-2, BRS-4, BRS-6, BRS-8, BRS-10, and BRS11 ofrelay BRS, make contacts AEV*3, AEV-4, AEV-6, AEV-8, AEV-10 and AEV-12of relay AEV and break contacts ARS-1, ARS-3, ARS-5, ARS-7, ARS-9, andARS-11 of relay ARS to the odd scan area.

The even pulse resulting from scanning the D digit is repeated fromground, make contacts ON-1 of relay ON (FIG. 6), AV-l of relay AV, PGE-1of relay PGE, break contact KP-Zt of relay KP, make contact AEV-27 ofrelay AEV, break contacts ARS-13 of relay ARS, CRS14 of relay CRS,DLOD-27 of relay DLOD, BS-Z3 of relay BS, make Contact DS17 of relay DS,break contact FS-Z and winding of relay FS to battery; relay FS operatesover this path and locks to ground through its FS-3 make contact andbreak contacts HS-l of relay HS, KS1 of relay KS and STS-1 of relay STSto lead 28.

When relay FS (FIG. 6) operates, the previouslytraced holding path forrelay DS is interrupted at break contact FS-I of relay FS but isimmediately transferred to make contact FS-18 and completed to groundthrough make contact DS-17 of relay DS, break contacts BS-23 of relayBS, DLOD-27 of relay DLOD, CRS-14 of relay CRS, and ARS-13 of relay ARS,make contact AEV-27 of relay AEV, break contact KP-Z4 of relay KP, makecontacts PGE-1 of relay PGE, AV-l of relay AV and ON-1 of relay ON.

Relay PGE releases at the end of the even D digit scanning cycle andthis is followed by release of relay DS since the above-traced holdingpath is interrupted at make contact PGE-1 of relay PGE.

Closed contacts of the F register relays F0, F1, F2, F4, and F7 (FIG.5), representing the next even digit of register F are now connected tothe even area of the scanning circuit through make contacts FS-4, FS-6,FS-8, FS-lt), and FS12 of relay FS, break contacts DS-5, DS-7, DS-9,DS-11, DS-13 and DS-15 of relay DS, break contacts of relays BS, DLODand CRS as previously described, make contacts AEV-14, AEV-17, AEV-18,AEV-21, AEV-23 and AEV-24 of relay AEV, break contacts KP-11, KP-13,KP-15, KP-17, KP-19 and IiP-21 of relay KP to the even scanning area.

The odd pulse resulting from scan of the E register digit is repeatedfrom ground, make contacts ON-l of relay ON (FIG. 6), AV-1 of relay AV,PGO-1 of relay PGO, AEV-26 of relay AEV, break contacts BRS- 13 of relayBRS, DLOD-26 of relay DLOD, AS-16 of relay AS, CS17 of relay CS, makecontact ES-16 of relay ES, break contact GS-Z and Winding of relay GS tobattery; relay GS operates and locks to ground through its make contactGS-S and break contacts IS-l of relay I S, LS-l of relay LS and STS1-1of relay STSL, lead 28, make contact ON-1 of relay ON to ground.

When relay GS operates the previously-traced locking path for relay ESis interrupted at break contact GS-1 of relay GS but is immediatelytransferred to make contact GS-lS and completed to ground through makecontact ES-16 of relay ES, break contacts CS-17 of relay CS, AS-16 ofrelay AS, DLOD-26 of relay DLOD, and BRS-13 of relay BRS, make contactsAEV-26 of relay AEV, PGO-1 of relay PGO, AV-l of relay AV and ON-1 ofrelay ON.

Relay PGO releases at the end of the odd digit scanning cycle and thisis followed by release of relay ES since the above-described holdingpath is interrupted at make contact PGO-1 of relay PGO.

Closed contacts of G register relays G0, G1, G2, G4, and G7 (FIG. 5) areconnected at this time to the odd scanning area through make contactsGS-4, GS-6, GS-S, GS-10, and GS-12, of relay GS, break contacts ES-5,ES-7, ES-9, ES-ll, ES-13, ES-lS of relay ES, break contacts of relaysCS, DLOD, AS and BRS relays as previously identified, make contactsAEV-3, AEV-'4, AEV-6, AEV-8, AEV-10 and AEV-12 of relay AEV, breakcontacts of relay ARS as previously identified to the odd scanning area.

The even pulse resulting from Ascan of the F register digit is repeatedfrom ground, make contacts ON-l of relay ON (FIG. 6), AV-1 of relay AV,PGE*1 of relay PGE, break contact KP-24 of relay KP, make contact AEV-27of relay AEV, break contacts ARS-13 of relay ARS, CRS-14 of relay CRS,DLOD-27 of relay DLOD, BS-23 of relay BS, DS-16 of relay DS, makecontact FS-16 of relay FS, break contact AIIS-2 and winding of relay HSto battery; relay HS .operates over this path and locks to groundthrough its own make contact HS-3, break contacts KS-l 'of relay KS andSTS-1 of relay STS to lead 28 and make contact ON-l of relay ON toground. K

When relay HS (FIG. 6) operates the previously-traced locking path forrelay FS is interrupted at break contact HS-1 of relay HS but isimmediately transferrd to make contact HS-18 and completed to groundthrough make contact FS-16 of relay FS, break contacts DS-16 of relayDS, BS-23 of relay BS, DLOD-27 of relay DLOD, CRS-14 of relay CRS, andARS-13 of relay ARS, make contact AEV-27 of relay AEV, break contactKP-24 of relay KP, make contact PGE-1 of relay PGE, AV-1 of relay AV andON-1 of relay ON.

Relay PGE releases at the end of the even F digit scan cycle; this isfollowed by release of relay FS since the above-traced holding path isinterrupted at make contact PGE-1 of relay PGE.

Closed contacts of H register relays H0, H1, H2, H4, and H7 (FIG. 5) arenow connected to the even scan area through make contacts HS-4, HS-6,HS-8, HS-10,

and HS-12 of relay HS, break contacts FS-S, FS-7, FS-9, FS-ll, FS-13 andFS-IS of relay FS, break contacts of relays DS, BS, DLOD and CRS aspreviously identified, make contacts AEV14, AEV-17, AEV-1S, AEV-2l,AEV-23 and AEV-24 of relay AEV, break contacts of relay KP as previouslyidentified to the even scanning area.

The odd pulse resulting from scan of the G register digit is repeatedfrom ground, make contacts ON-ll of relay ON (FIG. 6), AV-l of relay AV,PGO-1 of relay PGO, make contact AEV-26 of relay AEV, break contactsBRS-13 of relay BRS, DLOD-26 of relay DLOD, AS-lo of relay AS, CS-17 ofrelay CS, ES-17 of relay ES, make contact GS-16 of relay GS, breakcontact lS-Z' and Winding of relay JS to battery; relay JS operates andlocks to ground through its JS-3 make contact, break contacts LS-l ofrelay LS and STSl-l of relay STSTl, lead 28 to ground.

When relay JS (FIG. 6) operates the previously-traced locking path forrelay GS is interrupted at break contact .TS-1, but is immediatelytransferred to make contact JS-18 and completed to ground through makecontact GS-16 of relay GS, break contacts ES-17 of relay ES, CS-17 ofrelay CS, AS-16 of relay AS, DLOD-26 of relay DLOD, and BRS-13 of relayBRS, make contacts AEV-26 of relay AEV, PGO-1 of relay PGO, AV-l ofrelay AV and ON-l of relay ON.

Relay PGO releases at the end of the odd G digit scanning cycle and thisis followed by release of relay GS since the above-traced holding pathis interrupted at make contact PGO-1 of relay PGO.

Closed contacts of the I register relays J0, J 1, J2, J4, and J7 (FIG.5) are now connected to the odd scanning area through make contactsIS-4, .TS-6, JS-8, .iS-10, and .TS-12 of relay J S, break contacts GS-S,GS-7, GS-9, GS-ll, GS-13 and GS-IS of relay GS, break contacts of relaysES, CS, DLOD, AS, and BRS as previously identified, make contacts AEV-3,AEV-4, AEV-6, AEV- 8, AEV- and AEV-12 of relay AEV, break contacts ofrelay ARS as previously identified to the odd scan area.

The even pulse resulting from scan of the H register digit is repeatedfrom ground, make contacts ON-l of relay ON (FIG. 6), AV-1 of relay AV,PGE-1 of relay PGE, break contact KP-24 of relay KP, make contact AEV-27of relay AEV, break contacts ARS-13 of relay ARS,

. CRS-14 of relay CRS, DLOD-27 of relay DLOD, BS-23 of relay BS, DS-16of relay DS, and FS-17 of relay FS, make contact HS-16 of relay HS,break contact KS-Z and winding of relay KS to battery; relay KS operatesover this path and locks to ground through its make contact KS-S andbreak contact STS-1 of relay STS to lead 28.

When relay KS (FIG. 6) operates the previouslytraced holding path ofrelay HS is interrupted at break contact KS-l but is immediatelytransferred to make contact KS-lS and completed to ground through makeContact HS-16 of relay HS, break contacts FS-17 of relay FS, DS-16 ofrelay DS, BS-Z'S of relay BS, DLOD- -27 of relay DLOD, CRS-14 of relayCRS, and ARS-13 of relay ARS, make contact AEV27 of relay AEV, breakcontact KP-24 of relay KP, make contacts PGE-1 of relay PGE, AV-l ofrelay AV and ON- of relay ON.

Relay PGE releases at the end of the even H digit scanning cycle andthis is followed by release of relay HS since the above-traced holdingpath is interrupted at make contact PGE-1 of relay PGE.

Closed contacts of K register relays K0, Kl, K2, K4, and K7 (FIG. 5) arenow connected to the even scanning area through make contacts KS-l,KS-6, KS-S, KS-ltl, and KS-12 of relay KS, break contacts I-lS-5, HS-7,HS-9, HS-ll, HS-ll3 and HS-l of relay HS, break contacts of relays FS,DS, BS, DLOD and CRS Vas previously identified, make contacts AEV-14,AEV-17,

AEV-d8, AEV-21, AEV-23 and AEV-24?I of relay AEV,

1.2 break contacts of relay KP as previously identified to the evenscanning area.

The odd pulse resulting from scan of the l register digit is repeatedfrom ground, make contacts ON-l of relay ON (FL'G. 6), AV-l of relay AV,PGO-1 of relay PGO, AEV-26 of relay AEV, break contacts BRS-13 of relayBRS, DLOD-26 of relay DLOD, AS-lo of relay AS, CS-17 of relay CS, ES-l'7of relay ES, GS-17 of relay GS, make contact lS-ld of relay JS, breakcontact LS-2 and winding of relay LS to battery; relay LS operates overthis path and locks to ground through its make contact LS-3, breakcontact STSIt-l of relay STSll to lead 2S.

When relay LS operates the previously-traced locking path for relay l Sis interrupted at break contact LS-l but is immediately transferred tomake contact LS-ll and completed to ground through make contact JS-le ofrelay JS, break contacts GS-l of relay GS, ES-ll of relay ES, CSS-17 ofrelay CS, AS-ld of relay AS, DLOD-26 of relay DLOD, and BRS-13 of relayBRS, make contacts AEVZ6 of relay AEV, PGO1 of relay PGO, AV1 of relayAV and ON-l of relay ON.

Relay PGO releases at the end of the odd l digit scanning cycle and thisis followed by release of relay JS since the above-traced locking pathis interrupted at make contact PGO- of relay PGO.

Closed contacts of the L register relays L0, Ll, L2, Ll, and L7 (FlG. 5)are now connected to the odd scan area through make contacts LS-t, LS-5,LS-d, LS-7, and LS-S of relay LS, break contacts JS-S, lS-7, JFS-9,.lS--ll, JS-l3, JS-S of relay JS, break contacts of relays GS, ES, CS,DLOD, AS and BRS as previously identified, make contacts AEV-3, AEV-4,AEV-6, AEV-8, AEV-10 and AEV-l2 of relay AEV, break contacts of relayARS as previously identified, odd area of scanning circuit.

The even pulse resulting from scan of the K register digit is repeatedfrom ground, make contacts ON1 of relay GN (FiG. 6), AV-l, of relay AV,PGE-l of relay PGE, break contact ,KP-24 of relay KP, make ContactAEV-27 of relay AEV, break contacts ARS-13 of relay ARS, CRS-i4 of relayCRS, DLOD-27 of relay DLOD, 13S-23 of relay BS, DS-lti of relay DS,FS-17 of relay FS, HS-ll'? of relay HS, make contact KS-l of relay KS,break contact STS-2 and winding of relay STS to battery; relay STSoperates over this path and locks to ground through its make contactSTS-3 to lead 28.

When relay STS operates the previously-traced locking path for relay KSis interrupted at break contact STS-1 but is immediately transferred tomake Contact STS-4 and completed to ground through make contact KS-ltor" relay KS, break contacts HS-l of relay HS, FS-ll of relay FS, DS-ltof relay DS, 13S-23 of relay BS, DLGD-27' of relay DLOD, CRS-14 of relayCRS and ARS-l of relay ARS, make contact AEV-27 of relay AEV, breakcontact IiP-24 of relay KP, make contacts PGE-l of relay PGE, AV-l ofrelay AV and ON-l of relay ON.

Relay PGE releases at the end of the even digit K scan cycle and this isfollowed by release of relay KS since the above-traced holding path isinterrupted at make contact PGE-1 of relay PGE.

Following operation of relay STS the 2-of-6 combination (7 and 10) istransmitted in the ST digit position as an end-of-digits signal. Thepath for connection of the two permanently wired ground connections isthrough make contacts STS-4 and STS-5 of relay STS (FIG. 5), breakcontacts KS-l and KS-lS of relay KS, break contacts HS-l and HS-lS ofrelay HS, break contacts FS-IS and FS-lS of relay FS, break contactsDS-13 and DS-llS of relay DS, break contacts BS19 and BS-Zl of relay BS,break contacts DLOD-ll and DLOD-13 of relay DLOD, and break contactsCRS-lll and CRS-13 of relay CRS, make contacts AEV-23 and AEV-24 ofaiaaeaa 13 relay AEV, break contacts Kid-19 and KP-Zf of relay KP to theeven scan area of scanning circuit 25.

The odd pulse resulting from scan of the L register digit is repeatedfrom ground, make contacts ON-l of relay ON (FlG. 6), AV-l of relay AV,PGO-1 of relay PGO, AEV-26 of relay AEV, break contacts BRS-13 of relayBRS, DLOD-26 of relay DLOD, .AS-i6 of relay AS, CS-l7 of relay CS, ES-l'of relay ES, GS-17 of relay GS, IS-7 of relay .l S, make contact L84@ ofrelay LS, break contact STSl-Z and winding of relay STSl to battery;relay STSI operates over this path and locks to ground through its STS13make contact to lead 28.

When relay STSl operates the previously-traced holding path for relay LSis interrupted at break contact STSl-1 but is immediately transferred tomake contact STS1-4 and completed to ground through make contact LS-llof relay LS, break contacts lS-l7 of relay JS, GS-l7 of relay GS, IES-17of relay ES, CS-ll7 of relay CS, AS-16 of relay AS, DLOD-26 of relayDLOD, BRS-13 of relay BRS, make contacts AEV-26 of relay AEV, PGO-1 ofrelay PGO, AV-l of relay AV and ON-l of relay ON.

Relay PGO releases at the end of the odd digit L scan cycle and this isfollowed by release of relay LS since the above-traced holding path isinterrupted at make contact PGO-1 of relay PGO.

Relays STS and STSl release following release of relay ON and removal ofground from lead 28 and the steering circuit is then restored to normal.

It will be clear from the above description that a frequency shift pulsesender capable of high speed operation has been achieved because of thenovel feeding arrangement whereby odd and even digits are fedrespectively to series-connected odd and even areas of the scanningcircuit, and wherein, while the odd digit is being scanned, the evendigit is being connected to the scanning circuit and vice versa.Substantially continuous scanning is thus feasible. However, as pointedout above, addition of arbitrary digits and deletion of registereddigits are inherent in the operation of the sender and, when the feedingcircuit described above is utilized, these additions and deletions mustbe compensated for whereby to maintain proper steering of the digits.This follows from the obvious fact that addition of an odd nurnber ofdigits or deletion of an odd number will upset the prearranged alternatedistribution of the digits between the two feed paths. In accordancewith another aspect of our invention a novel reversing circuit has beenprovided for this compensating purpose and will now be described.

Two Arbitrary Digits Added; Three Registered Digits Deleted Let usassume now for purposes of further description, particularly with regardto the relay reversing arrangement, that in passing the callinginformation to the sender, two arbitrary digits have been added andthree registered digits have been deleted. It will be recalled from theabove description that relays DBR and DCR (FiG. 2) are operated when twoarbitrary digits are added; relay AEV (FlG. 4) will be operated;therefore, assuming relay ONl has operated, from ground, make contactONl-l of relay ONE., break contact DAR-ll of relay DAR, make contactDBR- of relay DBR, winding of relay AEV to battery. Also relay DLOD(FIG. 4) will be operated from ground, make contact ONl-l of relay ONll,make Contact DLS-1 of relay DLS, winding of relay DLOD to battery. Atthis time, therefore, relays AEV, DBR, DCR, DLS and DLOD are operated.Relays AEV and DLOD are reversing relays with reversing relay contactsas represented by captioned box 39 (FIG. 7) and as discussed above inconnection with FIG. 7.

Assuming that relays ON and AV have operated, relay KP (FlG. 6) operatesfrom ground, make contacts ON-l of relay ON and AV-l of relay AV, breakcontact SP-l of relay SP, break contact KP-l and winding of relay KP tobattery; relay KP upon operating locks to ground through its makecontact KP-Z, make contact AEV-1 of relay AEV, lead 27, break contactCRS-l of relay CRS, make contact DLOD-2S of relay DLOD, break contactsAS-l' of relay AS, CS-3 of relay CS, ES-l of relay ES, GS-l of relay GS,lSel of relay IS, LS-l of relay LS, STSll-l of relay STSI to lead 2S.Also, at this same time relay BRS (FIG. 6) operates from ground, makecontacts ON-l of relay ON, AV-ll of relay AV, break contacts SP-Z ofrelay SP and DAR-2 of relay DAR, make contact DBR-4 of relay DBR, breakcontact BRS-14 and winding of relay BRS to battery; relay BRS uponoperating locks to ground through its make contact BRS-Ilia', ead 4l,make contact DLOD-29 of relay DLOD, break contacts BS-l of relay BS, DS-of relay DS, FS- of relay FS, HS-l of relay HS, KS-l of relay KS, STS-lof relay STS to lead The KP register (FiG. 4) is immediately connectedto the even scan area through make contacts IiP-12, K13-14, KP-lb,KiP-i8, and IiP-22, therefore, while the closed contacts of the BRregister relays BRS, BRI, BRZ, BR4, and BR? (the first odd digit) areconnected to the odd scan area through make contacts BRS-ll, BRS-3,BRS-5, BRS-'7, and BRS-9 of relay BRS, make contacts AEV-3, AEV-4, AE-6, AEV-8, AEV-1G, AEV-l2 of relay AEV, break contacts ARS-l, ARS-3,ARS5, ARSJ, ARS-9, ARS-11 of relay ARS to the odd scan area.

The even pulse resulting from the scan of the KP register is repeatedfrom ground, make contacts ON-l of relay ON (FlG. 6), AV-l of relay AV,PGE-1 of relay PGE, KiP-23 of relay KP, break contact DAR-3 of relayDAR, make contact DBR-5 of relay DBR, break contact CRS-15 and windingof relay CRS to battery; relay CRS operates and loc is to ground throughits make contact CRS-16, make contact DLOD-23 of relay DLOD, breakcontacts AS-l of relay AS, CS-3 of relay CS, ES-l of relay ES, GS-ll ofrelay GS, IS-1 of relay IS, LS-l` of relay LS, STSl-L of relay STSl tolead 28.

When relay CRS operates the previously-described locking path for relayKP is interrupted at break contact CRS-1 but is immediately transferredto make contact CRS-18 and completed to ground through make contactDBR-5 of relay DBR, break contact DAR-3 of relay DAR, make contacts KP23of relay KP, PGE-1 of relay PGE., AV-l of relay AV and ON-l of relay ON.

Relay PGE (PEG. 4) releases at the end of the KP scan cycle and this isfollowed by release of relay KP since the above-traced locking path isinterrupted at make contact PGE-l of relay PGE.

Closed contacts of CR register relays CRtl, CRL CRZ, CR4, and CR7 (HG.4) are now connected to the even scan area through make contacts CRS-6,CRS-5, CRS-3, CRS-S, and CRS-lil of relay CRS, make contacts AEV-14,AEV-i7, AEV-itl, AEV-2l, AEV-23, and AEV-24 of relay AEV, break contactsKP-ll, KP-13, K13-l5, IiP-17, KiP-i9 and KP-Zl of relay KP, to even scanarea.

The odd pulse resulting from the scan of the BR register is repeatedfrom ground, make contacts ON-l of relay ON (PIG. 6), AV- of relay AV,PGO-1 of relay PGO, AEV-.26 of relay AEV, BRS-i6 of relay BRS, breakcontact DLI-2 of relay DLI., make contact DLS-4 of relay DLS, breakcontact DS-Z and Winding of relay DS to battery; relay DS operates andlocks to ground through its DS-3 make contact, break contacts FS-l ofrelay FS, HS-l of relay HS, KS-l of relay KS, and STS-1 of relay STS,lead 23, make contact ON- of relay ON to ground.

When relay DS operates, the previously-traced holding path for relay BRSis interrupted at break contact DS-l but is immediately transferred tomake contact DS-lS and completed to ground through make contact DLS-4 ofrelay DLS, break Contact DLl-Z of relay DLl, make contacts BRS-16 ofrelay BRS, AEV-26 of relay AEV,

i?! PGO-1 of relay PGO, AV-l of relay AV and GN-l of relay ON.

Relay PGO releases at the end oi the odd digit scanning cycle and thisis followed by release of relay BRS since the above-described holdingpath is interrupted at make Contact PGO-lt of relay PGO.

It will be observed that in View of the deletion of three registereddigits, registers A, B and C (PEG. 2) have been bypassed and relay DS(ElG. 6) operated as above described. Also it will be recalled from theprevious description that the D register relay contacts (FIG.representing an even digit, are normally connected as previouslydescribed to the even area of the scanning circuit. However, in thisinstance, as just described, the previous register relay CRS isconnected to the even area and it follows that if DS remained soconnected a gap in the scanning would ensue. The novel reversingarrangement provided compensates for this situation and transfers theconnection of the D register relay contacts to the odd scan area. Thiscorresponds to a transfer of path 3) (FIG. 7) from the even area to theodd area under control of reversing relay contacts 39 as previouslydescribed. The path for accomplishing this connection is traced throughmake contacts DS-ll, DS-d, DS-S, DS-ld, and DS12 (FIG. 5) of relay DS,break contacts BS-1L BS-l3, BS-lS, BS-, BSS-19 and BS-Zl of relay BS,make contacts DLOD-l, DLOD-l, DLOD-lll?, DLOD-Zl, DLOD-ZS and DLOD-ZS ofrelay DLOD (ElG. 4), break contacts AS-S, AS-S, A55-7, AS-9, AS-Ell andAS-ll of relay AS, break contacts BRS-Z, BRS-d, BRS-d, BRS-3, BRS-lu andBRS-Sil of relay BRS, make contacts AEV-3, AEV-1i, AEV-5, AEV-8, AEV-llland AEV-l2 or relay AEV, break contacts ARS-l, ARS-3, ARS-5, ARS-7',ARS-9, and ARS-lll of relay ARS tothe odd scan area.

The even pulse resulting from scan of the CR digit is repeated `fromground, make contacts ON-l of relay ON (FlG. 6), AV-l of relay AV, PGEflof relay PGE, break contact KP-Zd of relay KP, make contact AEV-27 ofrelay AEV, -break contact ARS-13 of relay ARS, make contact CRS-ll? ofrelay CRS, break con-tact DLl-S of rel-ay DLE, make contact DLS-5 ofrelay DLS, break contact ES-Z 'and winding of relay ES to battery; relayES opera-tes and locks to ground through its make contact ES-S, breakcontacts GS-l of relay GS, IS-l of relay JS, LS-TL of relay LS, SlSll-lof relay STSl, lead 28, make contact ON-il or" relay ON to ground.

When relay ES operates, the previously-described locking path `for relayCRS is interrupted at break contact ES-ll but is immediately transferredto make Contact ES- lS and completed to ground through make contact DL3-5 of relay DL3, break con-tact Dbl-3 of relay DLI, make contact CRS-17of relay CRS, break cont-act ARS-i3 of relay ARS, make contact AEV-27 ofrelay AEV, break con-tact Kil-24 of relay KP, make contacts PGE-1 ofrelay PGE., AV-l; of relay AV and @N41 of relay ON.

Relay PGE (FIG. 4) releases at the end of the even digit CRS scanningcycle land this is tollowed by release of relay CRS since theabove-described locking path is `interrupted at make contact PGE-l `ofrelay PGE.

Here again it will be recalled ifrom the previous description that theoperated contacts ofthe E register relays are normally connected to theodd scan area. In this instance, however, since the last path `from theDS relay was connected tothe odd area it is necessary for purposes ofcontinuous, rapid scanning that the ES relay be switched to the evenscan area. This is accomplished by the novel reversing circuit of .thepresent Iinvention over a path from make contacts ES-l, ES-6, ES-iil,ES-ltl, and EIS-l2 of rel-ay ES (EIG. 5 break contacts CS-S, CS-7, CS-9,CS2-lll, CS-lS and CS-lS of relay CS, make contacts BLOB-2, BLOB-4,BLOB-6, DLOD-S, DLOD-lltl and BLOB-3l?. of relay DLOD, break contactsCRSJ?, CRS-fl, CRS-2, CRS-9, CRS-Ill and CRSAl` of relay CRS, makecontacts AEVAM, AEV-17, AEV-18, AE-.Ve

21, AEV-23 and AEV-2d olV rel-ay AEV, break contacts KPll, KP-l, llJiS,lil-L17, Klhl and KP-Z ot relay KP to the even area ofi the scanningcircuit.

The odd pulse resulting from scan of the D register digit is repeated'from ground, make contacts ON- of relay ON (EiG. 6), AV-l of relay AV,PGO-1 of relay PGO and AEV-25 of relay AEV, break contacts BRS-13 0frelay BRS, make contact DLOD-Stl of relay DLOD, break Contact BS-Z ofrelay BS, make contact DS-ll' of relay DS, break Contact FS-Z andWinding of relay FS to battery; relay ES operates and locks to ground onlead 2S through its make contact FS-3v and break contacts H841 of relayHS, KS- of relay KS and STS-l of relay STS.

When relay FS operates, the previously-described holding pat-h forire-lay DS is interrupted at break contact FS-l but is immediatelytransferred .to make contact ES-18 and completed to ground through makeContact DS-l7 of relay DS, break contact 13S-213 of relay BS, makecontact DLOD-Sl` of relay DLOD, break contact BRS-13 of relay BRS, makecontacts AEV-2n of relay AEV, PGO-1 of relay PGO, AV-ll of relay AV, andON-l of relay ON.

Relay PGO releases at the end of the odd D digit scan cycle and this isfollowed by Irelease of relay DS since the above-described holding pathis interrupted `at make contact PGO-1 of relay PGO.

Since the last previous connection (ES) was to the even scan tarea it isnecessary to switch the ES connection from its normal path to the evenarea to the path leading tothe odd scan area. This is accomplished overthe path from make contacts FS-l, FS-d, FS-S, ES-Iltl, and FS12 of relayFS (FIG. 5), 'break contacts of relays DS and BS as previouslyidentified, make contacts DLOD-lS, DLOD-l', BLOB-19, BLOB-2l, DLOD23,and DLOD-25 of relay DLOD, break cont-acts of relays AS and BRS aspreviously identified, make contacts AEV-3, AEV-4, AEV-6, AEV-S, AEV-i9,AEV-l2 of relay AEV, break contacts of relny ARS as previouslyidentitled to the odd scan area.

The even pulse resulting trom scan of the E register digi-t is repeatedifrom ground, make contacts ON-l of rel-ay ON (FlG. 6), AV-l of relayAV, PGE-l of relay PGE, break Contact IiP-2d ot relay KP, make ContactAEV-Z7 of relay AEV, break contacts ARS-13 of relay ARS and CRS-14 ofrelay CRS, make contact BLOB-31 of relay DLOD, break contacts ASelo ofrelay AS, CS-17 of lrelay CS, make Contact ES-lo of relay ES, breakcontact GS-Z and winding of relay GS to battery; relay GS operates overthis path and locks to ground on lead 28 through its make contact GS-l`and break contacts JS-l of relay JS, LS-l of relay LS and STSl-l ofrelay STSl.

When relay GS ope yates, the previously-described lock- -ing path forrelay ES is interrupted at break contact GS-l but is immediatelytransferred to make contact GS-l and completed to ground through makeContact ES-16 of relay ES, break contacts CS-l7 of relay CS, AS-l6 ofrelay AS, make contact DEOD-3l of relay DLOD, break contacts CRS-ldofrelay CRS and ARS-13 of relay ARS, make contact AEV-2,7 of relay AEV,break contact KP-Z- of relay KP, make contacts PGE-l of relay PGE, AV-lof relay AV and ON-l of relay ON.

Relay PGE releases at the end of the even E digi-t scanning cycle andthis is followed by release of relay ES since the above-describedholding path lis `interrupted at make contact PGE-1 of relay PGE.

The closed contacts (EEG. 5) of the G register relays are now switchedyfrom their normal connection to the odd scan area to the even scantarea over la path trom make contacts GSI-4, GS-o, GS-S, GS-1tl, andGS-lZ of relay GS, break contacts of relays ES and CS as previouslyidentified, make contacts DLOD-2, DLODJ-l, DLOD-6, DLOD-S, DLOvD-ltl andDLOD-lZ of relay DLOD, break contacts of relay CRS as previouslyidentified, make Contacts AEV-d4, AEV-17, AEV-18, AEV- 2'1, AEV-23, andAEV-24 of relay AEV, break contacts of relay KP as previously ident-inedto .the even scan area.

The circuit operates in .a similar manner ,for scanning the remainingregisters .and restores .to Inonrnal upon cornpletion of fthe .cycle asdescribed above. It will be clear that by means `or the novel relayreversing circuit provided the :digits 4are automatically switchedbetween the even and odd paths in a manner .to maintain continuousscanning 'with proper alternating of connections between odd and eventareas even though the normal confection plan -is interfered with by theldeletion of the three digits. Also the various loacking paths for thesteering relays are reversed Ias required and steering relays ,arebypassed and additional steering relays `are operated as required by theaddition and deletion of digits.

One Arbitrary Digit Added; One Registered Digit Deleted For purposes offurther description let it be assumed now that a single arbitrary digitbe added and that a single lregistered digit be deleted. In this caserelays DCR, DL1 (FIG. 2) and DLOD (FIG. 4) will be operated while relaysDAR, DBR and AEV will be normal, or released. At the start of the cyclerelay KP (FIG. 6) operates, as described above, and in this instancelocks to ground through its make contact KP-2, break contact AEV-28 ofrelay AEV, break contact BRS-17 of relay BRS, make contact DLOD-29 ofrelay DLOD, break contacts BS-l of relay BS, DS-l of relay DS, FS-l ofrelay FS, HS-l of relay HS, KS-l of relay KS and STS-1 of relay STS tolead 23. At the same time relay CRS operates from ground, make contactsON-l of relay ON, AV-l of relay AV, break contact SP-Z of relay SP,break contacts DAR-2 of relay DAR and DBR-2 of relay DBR, make ContactDCR-4 of relay DCR, break contact CRS-l and winding of relay CRS tobattery; relay CRS upon operating locks toI ground on lead 28 throughits make Contact CRS-16, make Contact DLOD-Z8 of relay DLOD, breakcontacts AS- 1-7 of relay AS, CS-S of relay CS, ES-l of relay ES, GS-l`of relay GS, JS-l of relay IS, LS-1 of relay LS and STSl-l of relaySTSl.

At this time, therefore, the permanent ground on the O, 1, 2, 4, and 10leads is connected through the contacts of the KP relay and the path 30to the even scan area and the closed contacts of CR register relaysCRtl, CRI, CR2, CR4, and CR7 are connected to the odd scan area throughmake contacts CRS-6, CRS-5, CRS-3, CRS-8, and CRS-10 of relay CRS, breakcontacts AEV- 2, AEV-5, AEV-7, AEV-9, AEV-l1 and AEV-13 of relay AEV,break contacts ARS-l, ARS-3, ARS-5, ARS-7, ARS-9, ARS11 of relay ARS tothe odd scan area.

The even pulse resulting from scan of the KP digit is repeated fromground, make contacts ON-l of relay ON (FIG. 6), AV-l of relay AV, PGE-1of relay PGE, make contact KP-23 of relay KP, break contacts DAR-3 ofrelay DARV and DBR-3 of relay DBR, make contact DCR-S of relay DCR, makeContact DL1-5 of relay DL1, break contact BS-S and winding of relay BSto battery; relay BS operates over this path and locks to ground throughits make contact BS-9, and break contacts DS-l of relay DS, FS-l ofrelay FS, HS-l of relay HS, KS-l of relay KS, and STS-1 of relay STS tolead 28.

When relay BS operates, the previously-described locking path for rrelayKP is interrupted at break contact BS-l but is immediately transferredto make contact 13S-24 and completed to ground through make contactsDL1-5 ofrelay DL1 and DCR-5 of relay DCR, ybreak contacts DBR-3 of relayDBR and DAR-3 of relay DAR, make contacts IiP-23 of relay KP, PGE-1 ofrelay PGE, AV-I of relay AV and ON-l of relay ON.

Relay PGE releases at the end of the KP scan and this is followed byrelease of relay KP since the aboveiS described holding path isinterrupted at make contact PGE-1 of relay PGE.

Since the last previous connection (CRS) was to the odd scan area, the Bregister relay contacts should be connected to the even scan area. Thisis accomplished over a path through make contacts BS-ltl, BS-IZ, BS-ll,13S-16, and 13S-18 (FIG. 5) of relay BS, make contacts DLOD-15, DLOD-17,DLOD-19, DLOD-2l, DLOD-23 and DLOD-25 of relay DLOD, break contacts ofrelays AS and BRS as previously identified, break contacts AEX/45,AEV-16, AEX/49, AEV-Ztl, AEV-22 and AEV-25 of relay AEV, break contactsKP-ll, IiP-13, KP-lS, K12-17, KP-19 and KP-Zl of relay KP to the evenscan area.

The odd pulse resulting from the CR scan is repeated from ground, makecontacts ON-1 of relay ON (FIG. 6), AV-1 of relay AV, PGO-1 of relayPGO, break contacts AEV-29 of relay AEV, and ARS-13 of relay ARS, makecontacts CRS-17 of relay CRS, make contact DL1-4 of relay DL1, breakcontact CS-l and winding of relay CS to battery. Relay CS operates overthis path and locks to ground over its make contact CS- and breakcontacts ES-l of relay ES, GS-l of relay GS, l'S-l of relay IS, LS-l ofrelay LS and STSl-l of relay STSl to lead 28.

When relay CS operates, the previously-described holding path for relayCRS is interrupted at break contact CS-S but is immediately transferredto make contact CS-l and completed to lground through make contactsDLll-4 of relay DL1 and CRS-17 of relay CRS, break contacts ARS-13 ofrelay ARS and AEV-29 of relay AEV, make contacts PGO-l of relay PGO,AV-l of relay AV and ON-l of relay ON.

Relay PGO releases at the end of the odd digit scanning cycle and thisis followed by release of relay CRS since the above-described holdingpath is interrupted at make contact PGO-1 of relay PGO.

Since the last connection (BS) was to the even scan area, the C registerrelay contacts should be connected to the odd scan area. This isaccomplished over a path from make contacts CS-t, CS6, CS-S, CS-lt), andCS-lZ (FIG. 5) of relay CS, make contacts DLOD-2, DLOD-4, DLOD-6,DLOD-S, DLOD-lil and DLOD- 12 of relay DLOD, and break contacts ofrelays CRS, AEV and ARS as previously identilied to the odd scan area.

The even pulse resulting from the BS scan is repeated from ground, makecontacts ON-l of relay ON (FIG. 6), AV-l of relay AV, PGE-l of relayPGE, break contacts K13-24 of relay KP, AEV-3th of relay AEV, BRS-t3 Aofrelay BRS, make contacts DLOD-30 of relay DLOD and BS-ZZ of relay BS,break contact DS-Z and Winding of relay DS to battery. Relay DS operatesand locks to ground through its make Contact DS-3 and break contactsFS-l of relay FS, HS-ll of relay HS, KS4. of relay KS, and STS-1 ofrelay STS to lead 2S.

When relay DS operates, the previously-described holding path for relayBS is interrupted at break contact DS-l but is immediately transferredto make contact DS-l-S and completed to ground through make contactBS-ZZ of relay BS, make contact DLOD-3b of relay DLOD, break contactsBRS-13 of relay BRS, AEV-30 of relay AEV and KP-24 of relay KP, makecontacts PGE-1 of relay PGE, AV-l of relay AV and ON-l of relay ON.

Relay PGE releases at the end of the even digit scanning cycle and thisis followed by release of relay BS since the above-described lockingpath is interrupted at make contact PGE-1 of relay PGE.

The operated contacts of the D register relays Dil, D1, DZ, D4, and D7are connected to the even scan area through make contacts DS-4, DS-6,DS-8, DS-ltl, and D842 (FIG. 5) of relay DS, break contacts of relay BSas previously identified, make contacts DLOD-15, DLOD- 17, DLOD-19,DLOD-21, DLOD-23 and DLOD-25 of relay DLOD, break contacts of relays ASand BRS as previously identilied, break contacts AEV-15, AEV-lr6,AEV-119, AEV-2t), AEV-2.2 and AEV-25 of relay AEV, break contacts ofrelay KP as previously identified, to the even scan area.

The remaining register relay contacts are connected in turn for scanningin the manner described, and it will be noted that each register isconnected for scanning in the proper alternate odd-even manner eventhough both arbitrary addition and digit deletion has been effected.

Three Arbitrary Digits Added; Four Registered Digits Deleted As a stillfurther illustrative example it will be assumed that in passing thecalling information to the sender from the marker three arbitrary digitsare added and four registered digits are deleted. in this instancerelays DBR, DAR, DCR, DIA (PIG. 2) will be operated while relays AEV andDLOD (FIG. 4) are both released.

r:The KP relay (PEG. 6) operates over the path previously described butin this instance locks to ground through its make contact KP-Z, breakcontacts AEV-28 of relay AEV, BRS-17 of relay BRS, DLOD-SZ of relayDLOD, AS-l7 of relay AS, CS-3 of relay CS, ES-l of relay ES, GS-l ofrelay GS, JfS-l of relay JS, LS-l of relay LS, STSll-l of relay STSl,lead 2S, make contact ON-l of relay ON to ground. Also, relay ARS (FIG.6) operates at this time from ground, make contacts ONll of relay ON andAV-l of relay AV, break contact` SP-2 of relay SP, make contact DAR-4 ofrelay DAR, break contact ARS-M- and winding of relay ARS to battery.Relay ARS, upon operating, locks to ground through its ARS-l makecontact, break contacts CRS-l of relay CRS, DLOD-l of relay DLOD, BS-llof relay BS, DS-ll of relay DS, FS-l of relay FS, HS-ll of relay HS,KS-l of relay KS, and STS-l of relay STS, lead 2S, make contact ON-l ofrelay ON to ground.

Grounds representing the permanently connected KP digits are, as before,connected to the even scan area through make contacts (FIG. 4) of the KPrelay as previously identified, while closed contacts of the AR registerrelays ARQ, ARl, ARE, AR4, and AR7 are connected through make contactsARS-2, ARS-4, ARS-6, ARS-3, and ARS-lt) of relay ARS to the odd area ofthe scanning circuit for subsequent scan.

The even pulse resulting from the KP scan is repeated from ground, makecontacts ON-l of relay ON (FIG. 6), AV-i of relay AV, PGE-ll of relayPGE, IiP-23 of relay KP, and DAR-5 of relay DAR, break contact BRS-14and winding of relay BRS to battery. Relay BRS operates over this pathand locks to ground through its make contact BRS-15, break contactsDLOD-SZ of relay DLOD, AS-l7 of relay AS, CS-3 of relay CS, ES-l ofrelay ES, GS-l of relay GS, JS-ll of relay JS, LS-ll of relay LS andSTSl-l of relay STSl, lead 23, make contact ON-l of relay ON to ground.

When relay BR operates, the previously-traced locking path for relay KPis interrupted at break contact BRS-17 but is immediately transferred tomake Contact BRS-18 and completed to ground through make contacts DAR-5of relay DAR, KP-23 of relay KP, PGE-1 of relay PGE, AV-ll of relay AVand ON-l of relay ON.

Relay PGE releases at the end of the even KP scan cycle and this isfollowed by release of relay KP since the above-described locking pathis interrupted at make Contact PGE- of relay PGE.

Since the last previous register connection (ARS) was to the odd scanarea, the BR register relay contacts should, of course, be connected tothe even area. This connection is accomplished through make contactsBRS-l, BRS-3, BRS-5, BRS-7, and BRS-9 (FliG. 4) of relay BRS, breakcontacts AEV-l5, AEV-i6, AEV- 19, AEV-20, AEV-22 and AEV25 of relay AEV,break Y 2Q contacts of relay KP as previously identified to the evenscan area.

The odd pulse resulting from the AR scan is repeated from ground, makecontacts ON-l of relay ON (FIG. 6), AV-ll of relay AV and PGO-ll ofrelay PGO, break contact AEV-29 of relay AEV, make Contact ARS-16 ofrelay ARS, break contact CRS-15 and winding of relay CRS to battery;relay CRS operates over this path and locks to ground through its makecontacts CRS-16 and break contacts DLOD-l of relay DLOD, BS-l of relayBS, DS-l of relay DS, FS-ll of relay FS, HS-l of relay HS, KS- of relayKS and STS-1 of relay STS, lead 28 to ground on make contact ON-l` ofrelay ON.

When relay CRS operates the previously-traced holding path for relay ARSis interrupted at break contact CRS-3l but is immediately transferred tomake contact CRS-4S and completed to ground through make contact ARS-i6of relay ARS, break contact AEV-29 of relay AEV, make contacts PGO-l ofrelay PGO, AV-l of relay AV and ON-l of relay ON.

Relay PEO releases at the end of the odd digit AR scan cycle and this isfollowed by release of relay ARS since the above-traced holding path isinterrupted at make contact PGO-l of relay PGO.

The closed contacts of the CR register relays CRS, CRl, CRZ, CR4, andCR7 are connected at this time to the odd scan area through makecontacts CRS-6, CRS-5, CRS-3, CRS-8, and CRS-10 (FIG. 4) of relay CRS,break contacts AEV2, AEV5, AEV-7, AEV-9, AEV- ll and AEV-13 of relayAEV, break contacts of relay ARS as previously identied to the odd scanarea.

The even pulse resulting from the BR scan is repeated from ground, makecontacts ON-l` of relay ON (FIG. 6), AV-l of relay AV, PGE-1 of relayPGE, break contacts KP-24 of relay KP, and AEV-30 of relay AEV, makecontact BRS-16 of relay BRS, break contacts DLIl-Z of relay DLI, DLS-2of relay DLS, DLS-3 of relay DLS and DL-l of relay DL6, make contactDIA-3 of relay DL4, break contact ES-Z and winding of relay ES tobattery; relay ES operates over this path (it will be recalled that fourdigits were deleted) and locks to ground through its ES-3 make contactand break contacts GS-l of relay GS, JS-ll of relay JS, LS-l of relay LSand STSl-l of relay STSI to lead 28.

When relay ES operates the previously-traced holding path for relay BRSis interrupted at break contact ES-l but is immediately transferred tomake contact ES-lS and completed to ground through make contact DL4-3 ofrelay DIA, break contacts DL6-1 of relay DL6, DLS-3 of relay DLS, DLS-2of relay DLS, and DLI-2 of relay DLL make contact BRS-i6 of relay BRS,break contacts AEV-3h of relay AEV and KP-24 of relay KP, make contactsPGE-1 of relay PGE, AV-l of relay AV and ON-li of relay ON.

Relay PGE releases at the end of the even digit scan cycle and this isfollowed by release of relay BRS since the above-described locking pathis interrupted at make contact PGE-1 of relay PGE.

The closed contacts of the E register relays E0, E1, E2, E4, and E7 areconnected to the even scan area through make contacts ES-4, ES-6, ES-S,ES-lt) and ES-lZ (FlG. 5) of relay ES, break contacts of relay CS aspreviously identied, break contacts DLOD-14, DLOD-l6, DLOD-l, DLOD-Ztl,DLOD-ZZ., and DLOD-24 of relay DLOD, break contacts of relays AS and BRSas previously identied, break contacts AEV- 15, AEV-le, AEV-49, AEV-20,AEV-22 and AEV-25 of relay AEV, break contacts of relay KP as previouslyidentified to the even scan area.

The odd pulse resulting from the CR register scan is repeated fromground, make contacts ON-l of relay ON (FIG. 6), AV-l of relay AV,PGO-ll of relay PGO, break contacts AEV-29 of relay AEV, ARS-13 of relayARS, make contact CRS-17 of relay CRS, break contacts DLl-S of relayDLl, DLS-3 of relay DLS, DLS-4 of -ning cycle and this is 1 since theabove-described 'holding-path is'interruptedat 21 relay DLS, and DL62 ofrelay y'DL6, make' contact DL44 of relay DL4,'break contact FSLZandWinding of relay FSto battery; relay-FS operates and-locksftogroundthrough its FS-3 make contactandbreak contacts HS-l .of relay HS, KS-lof relay KS-and 'STS-IofrelaySTS Y of relay DLL make contact CRS-170irelay CRS, break contacts ARS-13 of relay ARS and -AEV29ofrelay relayAVand ON-I ofirelayON.

`Relay PGO releases'at the;end of the odd digit scanfollowed by releaseof `relay CRS make contact PGO-l ofrelay-PGO.

The Yclosed contacts of the `F register relaysFO, F1, F2, F4, and F7 areconnected to'theodd-'scan area through make contacts FS-'4,FS-:'6,'FS-8FS-10, and F8412 (FIG. of relay lFS, breakicontacts of relays DSand YBS as ,previously identified, break contacts DLOD-lS of relay DLOD,break contacts of relay- CRS as previously identified, break contactsAEV-2, AEVS, AEV-7, AEV-9, AEV-11 and lAEV-43 of relay AEV, breakcontacts of relay ARS- as previously-identified -to the odd scan area.

The even pulse resultingfrorn the E register scan is repeated fromground, make contacts ON-l of relay ON (FiG. 6), AV-l of relay AV, PGE-1of relay PGE, break contacts KP-24 of relay KP, AEV-30 of relay AEV,BRS-13 of relay BRS, DLOD-26 of relay DLOD, AS-ll6 of relay AS, andCS-17 of relay CS, make contact ES-16 of relay ES, break contact GS-Zand winding of relay GS to battery; relay GS operates over this path andlocks to ground through its make contact GS-3 and break contacts JS-l ofrelay JS, LS-l of relay LS and STSl-l of relay STSl to lead 28.

When relay GS operates, the previously-described locking path for relayES is interrupted at break contact GS- 1 but is immediately transferredto make contact GS-lS and completed to ground through make contact ES-lof relay ES, break contacts CS-17 of relay CS, AS-li of relay AS,DLOD-26 of relay DLOD, BRS-13 of relay BRS, AEV-30 of relay AEV andK13-24 of relay KP, make contacts PGE-1 of relay PGE, AV-l of relay AVand ON-l of relay ON.

Relay PGE releases at the end of the even digit scan cycle and this isfollowed by release of relay ES since the above-traced holding path isinterrupted at make contact PGE-1 of relay PGE. l

The closed contacts of the G register relays, G0, G1, G2, G4, and G7,are connected to the even scan area at this time through make contactsGS-4, GS-6, GS-S, GS-lti, and GS-lZ (FIG. 5) of relay GS, break contactsof relays ES and CS as previously identified, break contacts DLOD-14,DLOD-16, DLOD-18, DLOD-Zt, DLOD-22, and DLOD-24 of relay DLOD, breakcontacts of relays AS and BRS as previously identified, break contactsAEV-15, AEV-16, AEV-19, AEV-20, AEV- 22 and AEV-25 of relay AEV, breakcontacts of relay KP as previously identified to the even scan area.

The remaining registers are scanned in the manner described and it Willbe noted that again in this instance the connections are madealternately to the even and odd areas of the scanning circuit eventhough arbitrary digits have been added and registered digits have beendeleted.

While a specific embodiment of the invention has been selected fordetailed disclosure, the invention is not, of course, limited in itsapplication to the embodiment dissaid secondorder'area, means said'consecutivelyrelated registering-means in f-turn,

spective areas,l

`deletion of an odd number of registered digitsand `means .for-operatingsaid second rel-ay lupon addition to-an even closed The embodimentWhichhas been Adescribed should be taken as illustrative ofl theinventionrather than .as

.restrict-ive thereof.

What is claimed is: l. Ina pulse sender including aplurality of.consecultively related registering means for registering individualdigit information and meansfor adding arbitrary digits and deletingregistered digits, a scanning circuit including-a firstaorder-areaand asecond `orderarea, said areas lhaving a common output path, affrst lineand a-second line connected respectively to saidrst order areaand fortransmitting alternately over-said lines to said respective areasinformationffrom and `means for maintaining said alternaterelationshipof transmission When the consecutive relationship of the:registering means lis changed by additionof arbitrary digits vordeletion of registered digits.

-2. In a ypulse sender -the combination defined by` claim l furthercharacterized inthat said maintaining means includes a first and asecond relay effective upon operation to reversey theconnections of saidlines-tofthe remeans for operating-said first -relay upon number ofarbitrary digits.

3. -Inv a pulse sender including av plurality of registering meansforregistering individual digit information and means for addingarbitrarydigitsiand `deleting registered digits, ascanning circuit`includingfa first order area. and a second order area, a` first line anda-second-line connected respectively to said Yfirstv order areakfandsaid `second order area, means for connecting a first selectedgroup of said registering means to said first line and a second selectedgroup of said registering means to said second line, means fortransmitting registered information alternately over said first and saidsecond lines to said scanning circuit, and means effective upon deletionof a number of registered digits for reversing the connection of saidlines to said areas.

4. In a pulse sender, the combination defined by claim 3 furthercharacterized in that said number is an odd number.

5. in a pulse sender including a plurality of registering means forregistering individual digit information and means for adding arbitrarydigits and deleting registered digits, a scanning circuit including afirst order area and a second order area, said areas having a commonoutput path, a first line and a second line connected respectively tosaid first order area and said second order area, means for connecting afirst selected group of said registering means to said first line and asecond selected group of said registering means to said second line,means for transmitting registered information alternately over saidfirst and said second lines to said scanning circuit, and meanseffective upon addition of a number of arbitrary digits for reversingthe connection of said lines to said areas.

6. In a pulse sender, the combination defined by claim 5 furthercharacterized in that said number is an even number.

7. In a pulse sender including a plurality of registering means forregistering individual digit information and means for adding arbitrarydigits and deleting registered digits, la scanning circuit includ-ing afirst order area and a second order area, a first line land a secondline connected respectively to said first order area a-nd said secondorder area, means for connecting a first selected group of saidlregistering means to said first line and `a second selected group ofsaid registering means to said second line, means Afor transmittingregistered inform-ation alternately over said first and said secondlines to said scanning circuit, and means effective both upon deletionof an odd number =of registered digits and upon `addition 25B of an evennumber of arbitrary digits for reversing the connection of said lines tosaid areas` 8. In a frequency shift pulse sender including a pluralityof registering means for registering individual digit information andmeans 1for adding arbitrary digits and a iirst relay vand a secondrelay, `operation of each of said relays being effective to reverse theconnection of said lines to said areas, means effective upon theaddition of an even number of arbitrary digits for operating said firstrelay, and means effective upon the deletion of an odd number ofregistered digits for operating said second relay.

9. In a frequency shift pulse sender the combination defined by claim 8further characterized in that said connecting means includes a steeringrelay individual to each of said registering means, an `operating pathfor each of said steering relays, a iirst locking path for each of saidsteering relays effective when a respective relay operates to hold it in`operated position, and a second locking path for each of said steeringrelays, operation of said first relay and said second relay also beingeffective to interrupt the respective rst locking path for each operatedsteering relay and to complete 4the respective second locking paththerefor.

10. In a frequency shift pulse sender including a plurality ofregistering means `for registering individwal digit information andmeans `for adding arbitrary digits and deleting registered digits, ascanning circuit including a first order area and a second :order area,said tareas having a common output path, a lirst line and ta second lineconnected respectively to said rst order area and said second orderarea, means for connecting a first selected group of said registeringmeans to said rst line and a second selected group of said registeringmeans to said second line, means for transmitting information from oneof said first group of registering means Iover said first line to saidscanning circuit, means effective While said transmitted information isbeing scanned for transmitting information from one of said second groupof registering means over said second line to said scanning circuit `forsubsequent scanning, and means effective both upon addition of an evennumber tof arbitrary digits and upon deletion of an odd number ofregistered digits for reversing the connection `of said lines to saidareas.

11. In a telephone system, a sender comprising a scanning circuit havingan odd-scanning area and an even scanning area, a feed line connected toeach of said scanning areas, digit registering means, a digit steeringcircuit for :steering alternate digits to said feed lines, a digit beingsteered to one feed line -vvhile the priorly steered digit on the otherfeed line is being scanned, means for registering the addition anddeletion of digits, and means responsive to said last mentioned means'for reversing the connections of said feed lines to said scanningareas,

No references cited.

11. IN A TELEPHONE SYSTEM, A SENDER COMPRISING A SCANNING CIRCUIT HAVING AN ODD-SCANNING AREA AND AN EVEN SCANNING AREA, A FEED LINE CONNECTED TO EACH OF SAID SCANNING AREAS, DIGIT REGISTERING MEANS, A DIGIT STEERING CIRCUIT FOR STEERING ALTERNATE DIGITS TO SAID FEED LINES, A DIGIT BEING STEERED TO ONE FEED LINE WHILE THE PRIORLY STEERED DIGIT ON THE OTHER FEED LINE IS BEING SCANNED, MEANS FOR REGISTERING THE ADDITION AND DELETION OF DIGITS, AND MEANS RESPONSIVE TO SAID LAST MENTIONED MEANS FOR REVERSING THE CONNECTIONS OF SAID FEED LINES TO SAID SCANNING AREAS. 